ShellExecute crashes

I have a program which crashes on the ShellExecute() instruction. If I use the method system(), all works fine but I have read that system() was evil...

I'm using Visual Studio 2010 SP1.

So there is my function which calls ShellExecute:

ATC_GENERIC_API void __cdecl atcGenericLaunchGAG()
{
    HINSTANCE ret = ShellExecute( NULL, NULL, "MyExe.exe", NULL, "C:\\Opt\\", SW_SHOW );
    if( int(ret) > 32 )
    {
        //OK
        return;
    }
    //NOK
}

This is the error I have:

Unhandled exception at 0x640361c3 in Aneto Sol.exe: 0xC0000005: Access violation reading location 0x0ba29bb0.

And the debugger breaks here:

void __cdecl operator delete(void* p)
{
#if !defined(_AFX_NO_DEBUG_CRT) && defined(_DEBUG)
    _free_dbg(p, _NORMAL_BLOCK);
#else
    free(p);
#endif
}

And that is my call stack:

mfc100d.dll!operator delete(void * p)  Line 347 + 0xc bytes C++
mfc100d.dll!operator delete[](void * p)  Line 360 + 0x9 bytes C++
mfc100d.dll!CPlex::FreeDataChain()  Line 43 + 0xf bytes C++
mfc100d.dll!CMapPtrToPtr::RemoveAll()  Line 87 C++
mfc100d.dll!CMapPtrToPtr::FreeAssoc(CMapPtrToPtr::CAssoc * pAssoc)  Line 147 C++
mfc100d.dll!CMapPtrToPtr::RemoveKey(void * key)  Line 252 C++
mfc100d.dll!CHandleMap::RemoveHandle(void * h)  Line 230 C++

Is there somebody who already has had this kind of error with ShellExecute or who can explain to me why ShellExecute crashes like that ? Thank you for your help.

Solution

As Cory Nelson said, the error is not in the API itself, but in MFC. There might be a ShellExecute hook that causes your application to crash.